Wearable hearing aid having external microphone with penetrating pin connector structure



March 30, 1954 P. REICHERT 2,673,898 WEARABLE HEARING AID HAVING EXTERNAL MICROPHONE WITH PENETRATING PIN CONNECTOR STRUCTURE 6 Sheets-Sheet 1 Filed June 1 1951 I N V E N TOR. P1114 1P #6 CHE/7T 1! TTORNE Y March 30, 1954 p, RElcHERT 2,673,898

WEARABLE HEARING AID HAVING EXTERNAL MICROPHONE WITH PENETRATING PIN CONNECTOR STRUCTURE Flled June 1, 1951 6 Sheets-Sheet 2 I N V E N TOR. PHIL 1P Pele/ E 7' 0 M 7 I w l r/ I E 4 g HHHH I I 4 4 w W IIIIIIIIIIIII r M z N a a a e n E a\ u 3 IITTORNEY March 30, 1954 RElCHER-r 2,673,898

WEARABLE HEARING AID HAVING EXTERNAL MICROPHONE WITH PENETRATING PIN CONNECTOR STRUCTURE Filed June 1, 1951 6 Sheets-Sheet 3 E. 5A .1 IE E-A F a-z 7 Z 2/ 75 g T INVEN'IOR.

PHIL/P RE/CHERT ATTORNE Y March 30, 1954 P. REICHERT 2,673,898

WEARABLE HEARING AID HAVING EXTERNAL MICROPHONE WITH PENETRATING PIN CONNECTOR STRUCTURE Filed June 1, 1951 6 Sheets-Sheet 4 a "in I NV E N TOR. 3 firm/P Pele/rear A TTOR NE Y March 30, 1954 P. REICHERT 2,673,893

WEARABLE HEARING AID HAVING EXTERNAL MICROPHONE WITH PENETRATING PIN CONNECTOR STRUCTURE Filed June 1, 1951 6 Sheets-Sheet 5 Eli IN VEN TOR.

] PW: {P ram/aer- Z r, FM )7 0 March 30, 1954 P. REICHERT 2,673,898

WEARABLE HEARING AID HAVING EXTERNAL MICROPHONE I WITH PENETRATING PIN CONNECTOR STRUCTURE Patented Mar. 30, 1954 UNITED STATES A'rsr or Philip Reichert, New York, N. 11., assignor to Sonotone Corporation, Elmsford, N. Y., a corporation of New York Application June 1, 1951, Serial No. 229,386

7 Claims. (01. 179--107) This invention relates to microphone arrangements for wearable hearing aids, and more particularly to microphone arrangements for electron tube amplifier hearing aids, all the principal elements of which except for the receiver are usually housed in a flat, small casing worn inconspicuously behind or within the interior part of the garment of a user, although some aspects of the invention are of a broader scope.

This application is a continuation-in-part of application Serial No. 140,692 filed January 26, 1950.

Among the objects of the invention, a hearing aid of the foregoing type having an inconspicuous microphone unit arranged to be worn exposed on the exterior of the users garment so that it is not affected by clothes-rubbing noises, an electrical circuit connection including a connector pin structure having a garment-penetrating sharply pointed end which may be readily pushed through the garment, serving to connect the externally worn microphone unit to the amplifier worn hidden behind the garment of the user.

The foregoing and other objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawings, where- 1n:

Fig. 1 is a diagrammatic view of the general arrangement of one form of a wearable hearing aid combined with a microphone arrangement in accordance with the principles of the invention;

Fig. l-A shows a hard-of-hearing individual wearing the microphone unit of the invention on the exterior of the garment, the hearing aid amplifier hidden under the garment and connected to the microphone by a sharply-pointed garment penetrating connector pin structure of the external microphone;

Fig. l-B is a diagrammatic view of a variation of the microphone arrangement shown in Fig. 1;

Fig. 2 is a greatly enlarged cross-sectional view of one form of a microphone unit of the invention;

Fig. 2-A is a view similar to Fig. 2 showing a portion of the rear wall of the external microphone unit with a modified form of penetrating connector pin structure;

Fig. 3 is a greatly enlarged rear view of the microphone unit of Fig. 2 with its connector pin structure projecting therefrom into engagement with the terminals of the operating socket structure being shown in cross-section;

Fig. 4 is a cross-sectional view of the rear part of the microphone unit along lines 44 of Fig. 3;

Fig. 5 is an enlarged front view of an amplifier unit of the hearing aid having a microphone and amplifier elements housed in a flat casing, a part of the front wall of the amplifier casing being broken away to show portions of the interior structure;

Fig. 6 is a cross-sectional view of the amplifier unit of Fig. 5;

Fig. G-A shows a modified structure for connecting an external microphone to an amplifier;

Fig. 7 is a cross-sectional view of the socket or jack portion of the amplifier casing cooperating with the cord connector plug;

Fig. 8 is a side view of the socket structure of Fig. '7;

Fig. 9 is a cross-sectional view along lines 9-9 of Fig. 8;

Fig. 10 is a view similar to Fig. 9 with the plug connector in position;

Fig. 11 is a greatly enlarged view similar to Fig. 5 of a plug and. the upper half of the rear of a modified form of amplifier casing with a portion cut away to show the socket assembly;

Fig. 12 is a greatly enlarged side view of the upper portion of the amplifier casing of Fig. 11 showing openings for reception of a plug carrying the external microphone output.

Fig. 13 is a cross-sectional view of the socket portion of the amplifier casing, along lines 13-13 of Fig. 14;

Fig. 14 is a detail view of the socket structure of the amplifier casing;

Fig. 15 is a cross-sectional view of the external microphone of the type shown in Fig. l-B having the microphone plug in contact engagement therewith, taken along lines llil5 of Fig. 16;

Fig. 16 is a greatly enlarged rear view of the external microphone of Fig. 15; and

Fig. 17 is a cross-sectional view of the socket in the amplifier casing and the amplifier plug in contact engagement shown in Figs. 13, 14.

Most of the hard-of-hearing or deafened persons are very sensitive and seek to conceal their impairment. Accordingly, a practical hearing aid must be light, small and compact enough so that it may be worn comfortably and inconspicuously hidden behind a garment portion on the body of the user. In addition, it must be simple and fool-proof in operation and should require little attention so as to free the user from mental and physical strain and annoyance.

It is a general practice to make the hearing aid microphone an essential part of the amplifier unit, and house it directly behind a soundpervious wall portion of the front wall of the flat amplifier casing, but since such amplifier unit is as a rule worn behind a garment portion, frictional engagement of the garment with the front wall of the microphone casing produces rubbing noises which are picked up by the microphone and result in the transmission of highly disturbing amplifier clothes-rubbing-noises to the ear of the user.

Since most practical hearing aids operate with a high impedance microphone such as the piezoelectric microphone, it is essential that the corn nection of the microphone to the input terminals of the amplifier be shielded against pick-up of disturbing noise signals caused by electrical disturbances in the vicinity of the microphone. This is the reason why practically all hearing aids have the microphone unit housed within the amplifier casing close to the input terminals of the amplifier. Where the user desires to avoid cloth-rubbing noises, a shielded connector cord, usually in the form of a coaxial insulated conductor pair, is required to connect it to the amplifier casing worn behind the garment. Since the connector cord must be led to the amplifier unit over an exterior part of the garment, the exposed part of the connector cord causes annoyance to the user because it makes him conspicuous.

As a result, users of hearing aids generally prefer to suffer the annoyance or clothes-rubbing noises rather than wear on the exterior of the garment a microphone unit connected to the amplifier casing through a cord, part of which is exposed on the exterior of the garment. Therefore the only practical way to overcome this difiiculty was to wear the microphone on the wrist of the user and lead the cord through the sleeve of the garment to the amplifier casing.

Efforts have been made to overcome the difiiculty of exposing a part of the microphone cord on the exterior of the garment, either by providing each garment with a hole through which the microphone cord would be led from behind the microphone to the amplifier behind the garment, or as an alternative to carry the microphone on the wrist and lead the microphone cord through the sleeve to the amplifier casing. Both these alternatives are generally impractical. When a microphone is worn on the hand oi the user it transmits annoying sounds to the amplifier each time the hand moves. It is also a source of annoyance to provide each garment of a user with a special cord hole, particularly since this makes it necessary to wear the microphone on the same place on the exterior of the garment in order to cover up the hole in the garment.

According to the invention, the foregoing diniculties are overcome by connecting the externally worn microphone unit to the amplifier casing worn behind the garment-through detachable electrical connector elements including a sharplypointed garment-penetrating connector pin structure which completes the microphone connection by engaging with a cooperating socket connector structure.

In one 'form of the invention, the exteriorly exposed microphone unit is provided on its back with the projecting terminal elements in the form of a sharply-pointed garment-penetrating pin structure, thereby making is possible to utilize the pin structure of the microphone for attaching it to the garment, and at the same time provide by the portion of the pin structure which penetrates the garment the electrical connection from the microphone terminals to a terminal socket structure connected to the input terminals of the amplifier unit worn behind the garment of the user. In another form of the invention, the pins extend from a connector element in back 01' the garment and fit into electrical connector sockets in the microphone.

Fig. 1 shows diagrammatically the general arrangement of one form of a Wearable hearing aid based on the principles of the invention. It comprises an amplifier unit generally designated I and indicated therein by a dash-dot line enclosing all elements of the usual hearing aid, except for the receiver I 2. The dash-line amplifier enclosure of Fig. 1 represents the small, fiat amplifier casing shown structurally in Figs. 4 and 5, and which is small enough for inconspicuous wear under the garment of the user.

Referring to Fig. 1, the receiver l2, such as an ear-phone or bone receiver, is shown connected to the output terminals of the amplifier circuit of the hearing aid by two leads of a thin flexible cold it. Within the flat amplifier casing I0 is housed an electron tube amplifier including a first gain-stage tube 4, a second gain-stage amplifier tube 55, and a power-stage amplifier tube It. A microphone ll housed within the amplifier casing IQ (Figs. 4 and 5) impresses its signal output voltage on the control grid of the first gain-tube M, and an output transformer 18 delivers the amplifier output of power-tube I6 through cord It to the receiver l2.

The amplifier tubes Us, l5, [6 are supplied with electric power by a power unit including a tiny A-battery Ill-A which supplies heating current to the cathodes of the several tubes, and a tiny B-battery lit-B which supplies electric operating energy to the anode of the plate circuits of the several tubes.

A power supply control unit in the form of a three-position switch generally designated 2-H has a movable switch member 2-i2 provided with actuating member 2-l 3 accessible on the exterior of the amplifier casing for actuating the switch member 2I2 either in the on-full" position, or to the on-cut position, or to the oil position indicated in Fig. l by correspondingly labeled arrows. In the on-full position, the switch member 2--l2 completes an energizing circuit to the cathodes of the three tubes, thereby energizing the amplifier. In the ofF' position, the switch member 2i2 opens the energizing circuit to the cathodes of the three tubes.

The hearing aid amplifier is shown is also provided with an additional volume control structure generally designated 3--|l indicated as an adjustable tap rheostat 6-H connected across the output circuit of the first gain tube M, and a tap 3-i2 connected to the control grid of tube l5, so that by manually shifting the rheostat tap 3-42 by a control member, the user may adjust the sound output to the desired level.

The amplifier also includes the following additional circuit elements arranged in a manner generally similar to that in the co-pending application of R. W. Carlisle et .21., Serial. No. 129,374, filed November 25, 1949, and assigned to the assignee of the present application. A switch and control tone resistor I-R connected to the input side of the first gain tube M; circuit elements t-R, MR, 5-12., I i-R, Z-C, 3-0, 4-0, I i-C connected to the output side, and the screen grid of the first gain tube (4, capacitor 3-C serving as a part of a control circuit selectively setby the energizing switch 7-0 in the "on-cut position; circuit elements G-R, lfl-R, ii-C and 5-0 connected to the output circuit and the screen grid of the second gain tube i5, and to the input circuit of the first gain tube; and circuit elements li-R, iii-R developing the proper bias voltage for the power tube it, and the bypass condenser ii-C for the output transformer.

All of the above described elements of the amplifier unit it, except for the batteries are housed in the upper part of the amplifier casing shown in Figs. 5 and 6, the corresponding parts being shown in Figs. 5 and 6 by similar reference numerals. The microphone unit ii is carried suspended behind a soundpervious wall portion 2! of the front wall 22 of the casing is, which is usually worn hidden behind the garment of the user so that the sound-pervious wall portion 2! faces to the front for picking up sound and generating a corresponding voltage output impressed upon the amplifier. The batteries are usually housed in the battery compartment 23 provided in the bottom part of the fiat amplifier casing i ii.

As explained above, the user of such a hearing aid wearing the amplifier unit it with its microphone behind the garment has to suffer clothesrubbing noises picked up by the microphone when the garment moves relatively to the front wall 22 of the amplifier casing it behind which the microphone ll is positioned.

The present invention makes it possible for the user to pick up sound by the microphone unit made for instance in the form of a decorative ornament worn on the exterior of the garment, and provides a connection to the microphone unit which does not have any exposed cord portions which tends to embarrass many users.

In accordance with one form of the invention, the electrical circuit connection between the externally worn microphone unit and the amplifier unit worn behind the garment is provided by a detachable electrical connector including a sharply-pointed garment-penetrating connector pin structure arranged to engage a cooperating socket connector structure for completing a circuit connection for the external microphone unit to the amplifier input terminals with the amplifier casing worn behind the garment. The penetrating pin connector may be utilized and arranged to provide direct connection from the externally worn microphone unit to the encased amplifier unit worn directly behind the garment, or it may be made an intermediate part of a cord connection connecting the external microphone unit and the encased amplifier unit, or the like.

Fig. 1 indicates diagrammatically, and Figs. 2 to 4 show structurally, one form of a practical arrangement of an externally worn microphone unit provided with an inconspicious p netrating pin connector structure for connecting the external microphone unit to th input terminals of the encased amplifier unit behind the garment of the user.

An externally mounted microphone unit generally designated 3%? (Fig. l), is shown connected to the input terminals of the amplifier unit through a cord 3| shown in the form of a thin coaxial cord structure having an external cord lead 32 coaxial with and surrounding the inner conductor lead 33 which is insulated therefrom. Any available thin flexible cord leads are suit able for user as cord connection between an external microphone unit 38 and the input terminals of the high gain amplifier unit In of the type indicated in Fig. l. The cord 3| is shown arranged to be connected to the input terminals of the amplifier unit by a plug connector generally designated 3:3 insertable into a cooperating socket structure Mi exposed along the exterior of the amplifier casing.

The cord connector structure t i comprises two plug pins 36, 37 insulatingly held by and projecting from a plug member 38, and forming plug terminals for the two relatively insulated cord leads 32, 33 of the connector cord 3!. The plug pins 36, 3'1 are arranged to cooperate with a socket jack structure it provided within an exposed wall portion of the amplifier casing l9 and. having socket terminal members 42, 43 connected to the input circuit of the first gain tube Hi for supplying the output of the external microphone through the cord leads 32, 33 to the circuit of the first gain tube i i in lieu of the microphone output of the ampiifier ll enclosed within the amplifier casing it. The provision of such externally Worn microphone makes it unnecessary to provide an internal microphone H within the amplifier casing it, and thus further reduces its size.

In the form of the invention shown in Figs. 1 to 5, the plug and socket terminal elements 36, 31, 22 and 2-3, are so arranged that when the plug pins 3%, 3?? are inserted into contact engagement with the socket terminals 42, 43, the circuit connection between the internal microphone il housed within the amplifier casing I!) to the first gain tube M is broken. To this end the jack is of the amplifier casing it is provided with switch contact elements ll which are opened when the plug member 38 with its two plug pins 36, 3'! is in the plugged-in position shown in Fig. 1, the switch elements ii completing the circuit from the internal microphone i l to the gain tube M when the plug member is removed from its plugged-in position. With such arrangement, the user of the hearing aid has available the amplifier unit It with its built-in amplifier microphone ii for use in a conventional way without an external microphone. However, whenever he desires to use the external microphone unit 3i and thereby avoid clothes-rubbing noises, he has merely to plug in the connector plug of the external microphone to the amplifier socket structure it for connecting the external microphone unit 39 to the input terminal of the amplifier it, at the same time disconnecting and short-circuiting the internal amplifier microphone ll.

In the form shown in Figs. 1, 2., 3 and 4, the external microphone is provided with two externally exposed pin-shaped plug pin members iii, 52 exposed on the rear side of the external microphone unit it. The two plug pin members it, 52 may be made of stiff spring metal such as beryllium copper and they are provided with sharply pointed pin ends which readily penetrate the garment 56 such as a blouse, coat, overcoat or the like, worn by the user. The user is thus enabled to attach the microphone to the garment by pushing the plug pins 5%, 5-2 which are exposed behind the garment of the user, and without making any visible holes in the garment. This is indicated diagrammatically in Fig. i, and structurally in Figs. 2 where the microphone 3c is shown carried on an exterior side of a garment portion the two plug iii, 52 of the microphone having been pushed through the thickness or" the garment, and extending be- 7 hind the rear side of the garment portion 56, and holding the microphone unit against the front'side of the garment.

The cord 3| is shown provided with a flat socket member '60 housing two terminal socket terminal members 6|, 32 arranged for engagement with the pointed plug pins 52, of the microphone unit when the socket member is pushed over them in the manner shown in Figs. 2 to 4, and indicated diagrammatically in Fig. 1. As seen in Figs. 3 and 4, thesocket terminal anember 52 is held insulated within the socket structure 60, as by an insulating enclosure 63, the socket member 60 being made of metal, such as copper alloy to provide a shield enclosure around the plug connector elements 5|, 52, 6|, 62. The shielding cord conductor 32 of the cord is mechanically and electrically joined to the metallic socket enclosure member 60, which also serves as a direct support and electrical connection to the spring socket terminal member 6i, through which it establishes detachable contact engagement with the low potential or ground terminal member 5| of the external microphone 33.

Figs. 2 to 4 show details of one form of an external microphone unit of the invention, and its internal structure is similar to that described in the co-pending R. W. Carlisle, application Serial No. 86,560 filed April 9, 1949, and assigned to the assignee of the present application. It

comprises an outwardly tapering diaphragm 1: having a peripheral edge sealed and held amxed to the fiange of the circular rim 72 of the fiat rear wall T3 of the microphone casing. The central portion of the conical diaphragm ii is connected to a vibratory portion 22 of a vibro-electric transducer element 23 shown in the form of a piezoelectric crystal bi-rnorph structure suitably supported in a vibratory condition on the inner side of the microphone casing wall 73. The front side of the microphone casing 73 is enclosed by a front Wall '55 having a rim i6 suitably joined as by crimping to the rim 72 of the rear wall 13. The front wall T5 is .provided with openings rendering them sound-pervious and providing acoustic coupling between the diaphragm H of the microphone with the surrounding atmosphere for picking up sound, and converting it into corresponding electric output impressed through the cord leads 32, 33 on the amplifier. As indicated in Fig. 1-A, the exterior of the front wall 15 may be suitably ornamented so that the external microphone so shall serve as an ornament worn on an exterior part of the users garment.

The two exposed sharply-pointed plug terminals 5|, 52 projecting from the rear side of the external microphone 36 are suitably aifixed to its rear wall 73 so that the plug pin 52 which provides the circuit connection to the shielded insulated lead of the cord 3| is insulatingly supported'bythe casing wall 13. In the form shown, a hollow rivet member 3| of metal has its two end flanges crimped over insulating washers and spacers 82, 83 seated over a hole formed in a recessed wall portion i! of the microphone casing wall 13. The metallic rivet 3| has secured within its hollow interior an inward projection of the insulated plug pin structure 52 of the microphone, and forms a firm support holding it afiixed in its operative position. The inner end of the rivet 8| is suitably connected as by an insulated lead to one of the two conventional terminal leads of the piezoelectric transducer unit 23, the other terminal of the transducer unit "23 being connected to the metallic casing rear wall 13-01 the microphone unit. The other pin terminal member 5| of the microphone unit 30 is similarly secured with its inner end within another rivet member held afiixed to the recessed wall portion 11 of the microphone rear wall 13.

Figs. 7 to 10 show the structural details of one form of plug and socket connector through which the shielded microphone cord 3| is connected to the input terminals of the amplifier housed within the amplifier casing. Insulating wall portion 93 of the exposed narrow, insulating border frame of the amplifier casing In (Figs. 5, 6) has mounted therein two metallic contact terminal sleeves 42, 43, held aifixed at the inner end by split metal tabs 9|, 92 for retaining them in position and exerting an inward biasing action on the split inner arms of the two contact sleeve members 42, 43 which are shaped to engage and make contact connections with the two plug members 36, 31 of the cord connector plug 38 (see Figs. 5 and 10). The tab member 92 is connected to the high potential input lead of the amplifier, and the tab member 9| is connected to the lowpotential or ground input lead of the amplifier corresponding to the similar connections of the internal microphone H. An additional spring contact member made in the form of a metal spring 93 aflixed as by a rivet 94 to the insulating wall portion 98 of the frame member, is biased so as to make contact with an underlying bent contact portion 95 of the tab member 92 held extending from the terminal contact sleeve 43. When the cord plug member 38 is inserted into the socket structure 46, the low-potential plug pin 36 will actuate the spring contact member 93 to break its contact connection with the tab 95 of the terminal contact sleeve 43, and thus open the high-potential circuit of the internal microphone to the amplifier. As a result, at the moment when the two plug terminals 36, 31 complete the circuit connection of the external microphone unit 33 to the input terminals of the amplifier, the internal microphone H is disconnected from the input circuit and short-circuited. Removal of the plug pin 38 disconnects the external microphone from the amplifier unit and releases the spring contact arm 95 from the position shown in Fig. 10 to the position shown in Fig. 9, in which it completes the circuit connection from the high potential side of the microphone transducer terminal to the high potential input lead of the amplifier.

Fig. 6-A shows another way of combining, in accordance with the invention, an externally worn detachable microphone unit with an amplifier unit worn hidden in the garment of the user. The external microphone unit 3|! with the rearwardly extending penetrating contact pin elements 5|, 52, may be identical with that described above in connection with Figs. 1 t0 6. The amplifier unit Ill-2 may likewise be similar to that described in connection with Figs. 1, 5 and 6, except as shown, it may be without the internal microphone unit thus making it possible to correspondingly decrease its size. In addition, the receiver cord l 3 with its cord terminal |3-| is connected to a cord terminal socketplaced not on the top of the microphone unit as in the arrangement of Figs. 5 and 6but on the side of the microphone unit as shown in Fig. 6-A, corresponding to the socket structure 40 for the external microphone unit described in connection with Figs. '5 and 6. In the upper portion of the amplifier unit, there is mounted instead a socket structure B-I which may be generally similar to that shown at 00 in Figs. 1 to 4, so that the two penetrating contact pin elements 52, of the external microphone unit 30 may be inserted into the socket 30-I unit of the amplifier unit I0i, the amplifier unit socket 00-4 having contact terminal elements engaging the contact pins 56, E2 of the microphone unit for connecting them directly to the input terminals of the amplifier shown diagrammatically in Fist 1.

With the arrangement shown in Fig. 6-A, the external microphone unit 30 forms a unitary structure with the amplifier unit I0-2 mechanically and electrically directly connected thereto. However, the microphone unit may be readily detached from it for pushing the projecting penetrating contact pin elements 5|, 52, through a garment, indicated by the garment portions 56-I, 56-2, of Fig. 6-A, whereupon the amplifier unit 602 with its socket unit 60-I are brought into engagement with the amplifier contact pin elements 5I, 52, thereby completing the electrical as well as the mechanical connection between the externally worn microphone unit 30, and the amplifier unit I02 worn behind the garment. After insertion into the socket 00-4 of the amplifier unit Iii-2, the contact 7 pin elements 5|, 52 of the external microphone may be looked therein for instance by a swivel latch arm 9I-I pivotally mounted at 9I-2 on an adjacent wall portion of the amplifier unit I0-2 so that by turning the latch arm sidewise, the pin elements 5|, 52 of the external amplifier unit 30 may be released from or latched within their interfitting contact engagement with the terminal elements of the amplifier socket unit 60-4.

As shown in Fig. 6-A, by providing the amplifier unit I02 with a direct electrical and mechanical penetrating contact pin structure connection to the external microphone unit, the two are combined into a unitary structure which makes it possible to place the amplifier unit Iii-2 with the external microphone unit 30 detachably aflixed thereto directly over an edge -3 of a garment portion 50-4, forming part, for instance, of a coat pocket of a garment. With such arrangement, the resilient contact pin connector elements 5!, 52, serve as part of a clamp whereby the external microphone $0 overyling the outer surface of the garment portion 5tI holds the amplifier unit ill-2 clamped to the inner side of the garment portion.

Fig. Z-A shows an external microphone of the invention having a modified form of penetrating connecting pin structure.

The rear wall I3 of the microphone 30, such as described, above, is shown provided with a coaxial connector plug pin structure including an inner conductor pin member 52--I, insulated from a surrounding hollow outer conductor member 5II, the two conductor members forming the two terminals of opposite polarity through which the microphone unit is connected to the input terminals of the amplifier in a manner described in connection with Fig. 1.

The inner terminal member 52-I is provided with a sharply pointed penetrating pin, and is insulated along its entire length except for its exposed pointed outer end by an insulating layer 08. The inner ends of the two insulated coaxial pin structure members 5I-l, 52--I, are connected to the opposite terminals of the transducer Val 10 unit 23 of a microphone such as shown in Fig. 2; as described hereinbefore.

The cord socket 60 of Fig. 3 may be readily modified so that when it is placed over the coaxial pin structure of Fig. 6, one socket terminal will make contact with the exposed end portion of the inner insulated pin member 52-4, while the other socket terminal will make contact with the exterior portion of the pin structure 5II surrounding the inner pin structure 52I extending from the microphone rear wall 73.

Fig. l-B shows diagrammatically a modified form of an external microphone arrangement of the invention, Figs. l5, 16 showing the structural form thereof. The external microphone 2-30 is provided with socket terminal members I0 I,

instead of withplug connector elements arranged for detachable engagement with pointed plug prong members E03, I 04 or" an associated microphone plug I 22. As shown in Fig. 15, the socket terminal members IOI, I02 have the form of metallic sleeves of such diameter and length as to receive plug connector elements I03 and I04, respectively. Plug connector elements I03 and 600 are in the form of pins projecting from base members I00 and I 01 in plug enclosure member I05, as best shown in Figs. 15 and '16. Plug enclosure member I05 is molded of any suitable insulating material such as a common synthetic resin. Plug connector elements I03 and i104 may be made of stiff spring metal such as beryllium copper and they are provided with sharply pointed pin-ends I08 and I09 which readily penetrate garment H0 without leaving any visible holes therein. Cord leads 2-32 and 2-33 are connected mechanically and electrically to plug base members I 06 and I 07 which are held insulated from each other by the insulating enclosure member I05. The base members I00, I01 are of thin sheet metal and they form with the insulating enclosure body a fiat unit of only little thickness to prevent bulging of the overlying clothing.

Plug connector elements I03 and I04 have recesses H3 and H4 arranged to be releasably interlocked with portions of interlocking socket spring members H0, I20, respectively. The socket members IOI and I02 have slits H5, H6 into which the interlocking spring members IIO, I20 shown in the form of wire springs, are biased.

The external microphone of Figs. 15, 16 is otherwise very similar to that of Fig. 2. The microphone comprises an outwardly tapering diaphragm 2-'iI having a peripheral edge seated and held afiixed to the rim 2-12 of the flat rear wall 2l2 of the microphone casing. The central portion of the conical diaphragm 2-'II is connected to a vibratory portion 222 of a vibroelectric transducer element 223 shown in the form of a piezoelectric crystal lei-morph structure suitably supported in a vibratory condition on the inner side of the microphone casing wall 2'I3. The rear wall of the microphone casing 213 is secured to a front wall 2l5 by means of a front wall rim 2-?0 suitably joined, as by crimping, to the rim 2-42 of the rear wall 2-13. The front wall 2-15 is provided with openings rendering them sound-pervious and providing an acoustic coupling between the diaphragm 2-H of the microphone and the surrounding atmosphere for picking up sound, and converting it into corresponding electric output impressed through the cord leads 2-32 and 2-33 on the amplifier.

The microphone casing 2--13 as well as socket terminal members IOI and I02 is shown mounted in a housing I2I which may be made of an insulating plastic material. The housing I2I is provided along its front with an exterior rimmed casing wall I22, of metal, for instance, having openings for providing the acoustic coupling between the diaphragm 2-II and the surrounding atmosphere. The exterior casing I22 may, of course, be given any desired ornamental shape. The front ends of the socket terminal members I! and I02 are insulated from the casing I22 by insulating sheet portions I23, I24 which are connected over the housing openings, in which the socket terminal members are mounted. A soft fabric cushioning gasket I25 is suitably secured to the front wall 2-15 of the microphone unit to protect it against direct contact with exterior casing I22. The inner side of the soundpervious external casing wall I22 is covered with a sound-pervious, dust-impervious fabric I26, such as silk or rayon, to keep dust away from the microphone and serve as a damper for sound peaks. The rear of the microphone unit 2-30 has a back cover I2! of insulating material, such as fiber impregnated phenol formaldehyde con- 7 densation products, having holes in which the flanged hands of socket terminal members IOI, I02 are secured. The back cover I21 is further held aifixed to the casing I2I by four ears I28-I (Fig. 16), of the front casing I22 which are bent over the rear edge of back cover I21.

The externally mounted microphone unit generally designated 2-30 (Fig. 1-B) is connected to the input terminals of the amplifier unit through a cord 2-3I which is similar to that described in connection with the description of Fig. 1.

Figs. 11 to 14 and 1'7 show a modified form of plug connection between the other end of the cord 2-3I and the amplifier. The cord 2-3I (Fig. 11) is arranged to be connected to the input terminals of the amplifier unit by a plug connector, generally designated 2-34, insertable into a cooperating socket structure, generally designated 2-40, exposed along the exterior of the amplifier casing.

The cord connector structure 2-34 comprises fiat, bluntly pointed plug pins 2-30 and 2-31 insulatingly held. by and projecting from a plug member 2-38 and forming plug terminals for the two relatively insulated cord leads 2-32, 2-33 P of the connector cord 2-3I. The plug pins 2-36 and 2-31 are arranged to cooperate with a socket jack structure 2-40 provided within an exposed wall portion of amplifier casing 2-I0 (Fig. 12) and having socket terminal members 2-42 and 2-43. The socket terminal members 2-42, 2-43 are connected to the input circuit of the first gain tube I4 of the amplifier for supplying the output of the external microphone 2-30 through the cord leads 2-32 and 2-33 to the circuit of the first gain tube I4 in lieu of the microphone output of the internal microphone I'I enclosed within the amplifier casing 2-I0. The amplifier circuit may be identical with that shown schematically in Fig. 1.

Referringv to Figs. l1, 17, the plug connector has an insulating cover 2-38 insulatingly molded about the electrical and mechanical connections of cord leads 2-32 and 2-33 of coaxial cord 2-3I to plug pins 2-36 and 2-3I, respectively. The embedded ends of the plug pins 2-30 and 2-3'! are curved to form seats in which are clamped metallic eyelets I29 and I30 which are clamped to the coil lead ends, and insulatin washer I3I separating the two eyelets I29, I30.

Figs. 12 to 14 show the microphone input socket assembly of the amplifier unitof Fig. 1. Adjacent the interior of the narrow border wall 2-40 of the casing 2-I0 (Figs. 11, 12) is mounted terminal plate I33, which is made of a stiff insulating material, such as resin impregnated fiber. The casing border wall 2-40 is provided with suitable openings, I34, I35 (Fig. 12) to receive plug pins 2-36, 2-31. Terminal plate I33 is provided with openings I34-I, I35-I which register with plug pin openings I34, I35 in casing 2-l0 for receiving the inner ends of the plug pins 2-36, 2-31.

Terminal plate I33 is also provided with looped socket terminal members 2-42, 2-43 which are afiixed thereto by means of rivets I36, I31 which also serve as contacts for leads to first gain tube I4 and to ground, respectively. Socket terminal members 2-42, 2-43 are shown made of spring wire and each includes two arms I50, I5I and I52, I53, respectively. Arms I53 and I50 are secured to terminal plate I33 at their bent ends I53-l, I50-I, respectively, by metallic brackets I53-2, I50-2, respectively, (Fig. 14). The other arms I5I, I52 of socket terminal members 2-42, 2-43, respectively, are spring biased to the positions shown in Fig. 14 so that they may flex away from their fixed arms by plug pins 2-36, 2-31, inserted therebetween. Arms I50, I5I and I52, I53 of socket terminal members 2-42, 2-43 are so disposed and biased to pass directly behind socket openings I34-I, I35-I in terminal plate I33, and to establish contact engagement with portions of the two plug pins 2-36, 2-31 of the cord plug 2-34 in its coupled position (Fig. 17) It will be noted that, as shown in Figs. 11 and 17, plug pin 2-35 is of greater width than is plug pin 2-31. Openings I34, I35 and I34-I, I35-I are similarly polarized and correspond in size so as to prevent inserting plug 2-34 into socket I32 in reverse position.

As shown in Figs. 13, 14, the terminal plate I33 is also provided with switch element 2-41 having a fixed end 2-48 which is secured to metal bracket I39 of the terminal plate. The switch element 2-41 remains in fixed electrical contact engagement with terminal post I40 through which it is connected to the internal microphone IT. The flexible contact spring arm I5I of the plug socket is spring biased to remain in releasable contact engagement with the fixed switch arm 2-4! as long as the cord plug pins are disengaged from the socket.

In the form shown in Figs. 11-14 and Fig. 17, the plug and socket terminal elements 2-30, 2-31 and 2-42, 2-43 are so arranged that when the plug pins 2-36 and 2-31 are inserted into contact engagement with socket terminals 2-42, 243, the circuit connection between the internal microphone I'I housed within the amplifier casing I0 and the first gain stage tube I4 is broken.

When plug 2-34 is inserted into contact engagement with socket I32, plug pin 2-36 forces the spring contact arm I5I downwardly into position shown at I5I-I (Fig. 14) and out of contact with switch element 2-41 thereby breaking the connection of the internal microphone I! while contact spring I50 completes the connection to the external microphone 2-30. At the same time, plug pin 2-37 forces spring contact arm I52 upwardly with the position shown at I52-I (Fig. 14).

When plug pins 2-36, 2-31 are inserted into contact engagement with socket spring terminal members 2-42, 2-43 (Figs. 17, 13, 14), the stationary spring arms I53 and I50 together with 13 adjacent flexible spring contact arms ll, I 52 serve to guide the plug pins into contact engagement therewith, respectively. Recess I38 in plug pin Z-3'l engages arm 552 so that plug 2-3B is releasably held in the closed contact position.

With such an arrangement, the user of the hearing aid has available the amplifier unit with its built-in amplifier microphone ll for use in a conventional Way without an external microphone. However, when the user desires to use the external microphone unit 2-39, and thereby avoid clothes-rubbing noises, he has merely to plug in the connector plug of exteral microphone 39 to the amplifier socket structure I32 for connecting the external microphone unit 2--39 to the input terminal of the amplifier, at the same time disconnecting circuit for the internal microphone I'i.

Various other modifications of the invention will suggest themselves to those skilled in the art. It is accordingly desired that in construing the breadth of the appended claims, they shall not be limited to the specific details shown and described in connection with the exemplifications of the invention.

I claim:

1. In a hearing aid including an inconspicuously small amplifier casing enclosing substantially all elements of an electron tube amplifier, and designed for cooperation with a separate microphone unit embodying a sound transducer structure arranged to be connected to the input terminals of said amplifier, and in combination therewith one set of metallic connector elements embodying at least one mechanically stiff metallic connector pin structure provided with a relatively sharply pointed pin-end shaped to penetrate the thickness of a garment and a cooperating set of metallic connector elements constituting a contactor structure arranged for detachably receiving said pin structure and mechanically retaining said cooperating set of connector elements in a position wherein said two sets of metallic connector elements complete electric circuit connections between the transducer structure of the separate microphone unit and the input terminals of said amplifier whereby said microphone unit may be worn on the exterior of a garment and connected to said amplifier by insertion of the connector pin structure through the thickness of the garment into said contactor structure.

2. In a hearing aid including an inconspicuously small amplifier casing enclosing substantially all elements of an electron tube amplifier together with an associated internal microphone and electric power source and designed for cooperation with a separate microphone unit embodying a sound transducer structure arranged to be connected to the input terminals of said amplifier, and in combination therewith, one set of connector elements embodying at least one mechanically stiff metallic connector pin structure provided with a relatively sharply pointed pin-end shaped to penetrate the thickness of a garment and a cooperating set of metallic connector elements constituting a contactor structure arranged for detachably receiving said pin structure and mechanically maintaining said cooperating set of metallic connector elements in a position wherein said two sets of metallic connector elements complete electric circuit connections between the transducer structure of the separate microphone unit and the input terminals of said amplifier whereby said microphone unit may be worn on the exterior of a garment and connected to said amplifier by insertion of the connector pin structure through the thickness of the garment into said contactor structure, said amplifier casing also embodying disabling elements operative to disable said internal microphone when said separate microphone unit is connected through said circuit connections to said amplifier, said disabling elements including means operative to restore the operativeness of said internal microphone when said circuit connections are broken.

3. In a hearing aid as claimed in claim 1, one of said connector elements forming part of said separate microphone unit.

4. In a hearing aid as claimed in claim 2, one of said connector elements forming part of said microphone unit, the set of connector elements embodying said connector pin structure having two projecting electrically relatively insulated metallic connector pins each with a sharply pointed pin-end and a cooperating contactor structure having two relatively insulated metallic portions engaging said two metallic connector pins.

5. In a hearing aid as claimed in claim 1, one of said two sets of metallic amplifier connector elements being a part of and carried by said amplifier casing whereby said separate microphone unit is directly carried through said contact pin structure by said amplifier casing.

6. In a hearing aid as claimed in claim 2, said one set of metallic amplifier connector elements being a part of and carried by said amplifier casing whereby said separate microphone unit is directly carried through said contact pin structure by said amplifier unit.

7. In a device of the class described, a cuplike casing, a microphone within said casing, an anchoring pin extending through the closed end of said casing and projecting laterally outwardly therefrom, said anchoring pin being formed from electrical conducting material and being pointed at its outer end to facilitate penetration of the garment of the wearer, electrical conduit means within said casing connecting said microphone to said anchoring pin, and female connector socket means adapted to make connection with and enclose the pointed end of said anchoring pin on the opposite side of the garment of the wearer, said anchoring pin being provided with an angular outer end portion which extends in a direction substantially parallel to the plane of the bottom wall of said casing.

PHILIP REICHERT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 313,726 Haid Mar. 10, 1885 466,725 Miltimore Jan. 5, 1892 1,318,874 Houghiemstra Oct. 14, 1919 1,666,729 Bick et al. Apr. 17, 1928 1,689,692 Sell Oct. 30, 1928 1,709,747 Sell Apr. 16, 1929 1,826,797 Leach et a1. Oct. 13, 1931 2,182,865 Franzblau Dec. 12, 1939 2,321,370 Dubilier Jan. 8, 1943 2,582,287 Shaper Jan. 15, 1952 

